Show that the product of is an even number. This proof requires elementary knowledge in algebra and some manipulation of symbols. It is assumed that you already know or have proved that the sum of two even numbers is even, the sum of two odd integers is odd, and the sum of an odd number and […]

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# Yearly Archives: 2014

## Base Angles of Isosceles Triangles are Congruent

Proof is probably one of the most difficult concepts to teach in high school mathematics. In this short post, we are going to discuss a simple activity that can be used in teaching mathematical proofs in Geometry. First, we can use a rectangular paper, fold it in the middle, and cut through the diagonal. Of course, […]

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## Quadrilaterals With Congruent Opposite Angles Are Parallelogram

In the previous post, we have proved that if the opposite sides of a quadrilateral are congruent, then they are parallel. In this post, we are going to show that if the opposite angles of a quadrilateral are congruent, then it is a parallelogram. In the figure below, we have quadrilateral ABCD with and . […]

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